Engine throttle control mechanism



April 27, 1965 D. "r. AYERS, JR

ENGINE THROTTLE CONTROL MECHANISM Filed Aug. 9, 1.962

3 Sheets-Sheet 1 INVENTOR DAVID T. AYERS, JR.

ATTORNEY April 27, 1965 D. T. AYERS, JR

ENGINE THROTTLE CONTROL MECHANISM 3 Sheets-Sheet 2 Filed Aug. 9, 1962 mp on vb l 3 m em M 1 I f M 3 mm on ma MJ Ms R E Yu A D V A D ATTORNEY April 1965 D. 'r. AYERS, JR 3,180,232

ENGINE THROTTLE CONTROL MECHANISM Filed Aug. 9, 1962 3 Sheets-Sheet 3 (D an In INVENTOR DAVID T. AYERS, JR.

ATTORNEY United States Patent "ice,

3,180,232 ENGINE THROTTLE CONTROL MECHANISM David T. Ayers, In, Birmingham, Mich, assignor to Kelsey-Hayes Company, Romulus, Mich, a corporation of Delaware Filed Aug. 9, 1962, Ser. No. 215,915 17 tllaims. (Cl. 31-415) This invention relates to an engine throttle control mechanism, and more particularly to a throttle control for a motor vehicle engine.

An important object in the invention is to provide novel means for operating a vehicle engine throttle from a low-positioned treadle which travels only a very slight distance for effecting movement of the throttle valve through its full range of operation.

A further object is to provide such a mechanism wherein the arrangement of the throttle control pedal at a low position facilitates its use under normal conditions with a more comfortable foot operation through a limited range of movement and wherein, used in conjunction with a power brake mechanism, the throttle treadle and brake treadle may be normally arranged substantially at the same height.

A further object is to provide the operation of the carburetor throttle lever through the medium of a fluid pressure motor the valve mechanism of which, for a full throttle operation, is controlled by a treadle which partakes of very short movement between an idling position and a fully open throttle position.

A further object is to provide such a mechanism wherein the fluid pressure motor is operable by differential pressures provided through vehicle engine operation and wherein, it the power for the throttle operating motor fails, the treadle will move to a higher position from which it is movable through a conventional range for the full manual operation of the throttle lever.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the drawings I have shown two embodiments of the invention. In this showing FIGURE 1 is a side elevation of the mechanism showing the throttle lever, its connection with its operating motor and the control means connected to such motor;

FIGURE 2 is an enlarged fragmentary sectional view through the throttle lever operating motor, the parts being shown in the normal positions they will occupy upon a failure in power for the motor;

FIGURE 3 is a similar View showing the parts in the positions they will occupy when power is present for operating the motor, and

FIGURE 4 is a detail fragmentary sectional view of a modified type of control valve for the fluid pressure motor.

Referring to FIGURE 1 the numeral 9 designates a motor vehicle engine having conventional carburetor it) provided with a throttle (not shown) controlled by a conventional throttle lever 11 pivoted to the carburetor as at 12. The lever 11 is shown turned counterclockwise to idling position beyond which it cannot turn. The free end of the throttle lever is pivoted as at 13 to a throttle rod 14- leading to a fluid pressure motor indicated as a whole by the numeral I and described in detail below. The rod 14 is provided with a bracket 16 to which is connected a return spring 17 having its other end fixedly connected as at 18 at any fixed support such as the vehicle engine. The spring 17 normally holds the throttle lever 11 in its idling position.

The motor 15 is preferably operable by differential pressure provided through the functioning of the vehicle engine and shown in the present instance as a vacuum 3,i8@,232 Patented Apr. 27, 1965 motor adapted for connection with the intake manifold of the vehicle engine as a source of vacuum. The motor comprises a cylinder 22 having a piston 23 mounted therein and biased to the position shown in FIGURE 2 by a spring 24 one end of which engages the piston 23 while the other end engages the head 25 of the cylinder 22. A piston rod 28 is fixed to the piston 23 and is slidable through bearing and sealing means 29 in the head 25. Externally of the cylinder 22, the piston rod 28 is secured as at 30, for example by threading, to the adjacent end of the throttle rod 14.

The cylinder 22 is provided at the end opposite the head 25 with a head 35, and the piston 23 forms respectively with the heads 25 and 35 a pair of chambers 36 and 37. Atmospheric pressure is always present in the chamber 37. Under normal operating conditions, as described below, vacuum is present in the chamber 36 under which conditions the piston 23 occupies the position shown in FIGURE 3. When the vacuum in the source fails, as described below, atmospheric pressure will be present in the chamber 36, in which case the parts will occupy the normal positions shown in FIGURE 2.

Since the throttle rod 14 is sometimes bent and thus subjected to some twisting force during its operation it is advisable to provide means for preventing turning of the piston 23 on tis own axis. To this end, a rod 38 may be fixed at one end to the piston 23 with its other end slidable through the head 35.

A valve mechanism indicated as a whole by the numeral itl controls the operation of the motor 15. In the form of the invention shown in FIGURES 2 and .3 the valve mechanism comprises a body 41 having two ports 42 and 43 the former of which is connected by a line 44 to the source of vacuum such as the engine intake manifold (not shown). The port 43 is connected by a jumper line 45 to a fitting 46 communicating with the chamber 36.

A slide valve 5a is axially movable in a bore 51 formed in the body 41 and is annularly grooved as at 52 to provide a passage which is in fixed communication with the inner end of the port 42 and is normally in leaking communication with the reduced inner end of the port 43 in a valve position approximating that shown in FIGURE 3. In the normal power-operative position of the parts in FIGURE 3, therefore, vacuum is maintained in the chamber 36.

The valve 50 is provided with an annular groove 54 separated from the groove 52 by a land 55 which normally closes communication between the port 43 and groove 54. The latter groove communicates through a port 56 with a bore 57 formed in the valve 50. Within this bore is arranged a return spring 58 one end of which is seated in the bottom of the bore 57 and the other end of which engages the head 35, thus normally biasing the valve 50 to engagement with a stop ring 59. A port 61 communicates between the bore 57 and a chamber 62 within a boot 63 which extends between the valve body 41 and an axial stem 64 preferably formed integral with the valve 50. The bore 57 communicates with the motor chamber 37 through a port 66 formed in the head 35. A contact button 67 is carried by the free end of the stem 64, and when power is available for operating the motor 15, the button s7 engages a stop 68 carried by any suitable type of stationary support 69. An air cleaner 74 may be fixed by a retainer 75 to the cylinder 22. Air through the cleaner 74 may flow into the chamber 37 through a port 76.

'The head 35 carries a pair of ears 78 supporting a pin 79 on which is pivoted the upper end of a lever 80. This lever is pivotedly supported in any suitable manner as at 81 FIGURE 1 below which pivot point the lever is bent as shown in FIGURE 1 to terminate in a lower end 82.

The lower extremity of such lever is bent to form an arcuate contact surface 83 bearing against the bottom of a treadle lever 34 arranged in the usual position above the toeboard 85 of the vehicle and pivotedly supported at its lower end as at 86. The treadle S4 and the lower end of lever 82 have been shown in solid lines in FIGURE 1 in the positions they will occupy when the engine is not operating and no power is available for operating the motor 15. This may be designated as position A from which position, for full manual throttle operation, the treadle moves to a point close to the toeboard 85. The treadle occupies position B when released and vacuum is present in the motor 15, and full throttle operation takes place between such position and position C, as further described below.

In the form of the invention described above, leakage around the valve will result shortly after the vehicle engine is turned off or stalls, and the treadle 84 moves up to position A. In the modified form of the invention in FIG- URE 4, a valve sealing feature and other means cooperate to seal the valve so that the motor piston 23 will remain for substantial periods of time in the position shown in FIGURE 4 by maintaining in the chamber 36 a suflicient degree of vacuum to hold the spring 24 compressed. In FIGURE 4, parts corresponding to those in the form of the invention described have been indicated by the same reference numerals.

Referring to FIGURE 4, the stop ring 59 has been eliminated and a resilient sealing ring 99 is arranged against a shoulder 91 in the housing 41 and engages the adjacent end of the valve 50 in the olf position of such valve. The vacuum pipe 44, leading to the intake manifold, is provided with a check valve 92 so as to trap vacuum in the valve device in the event the motor stalls.

Between the check valve 92 and valve body 41 a pipe 93 connects the pipe 44 to a vacuum reservoir 94.

Operation Operation of the form of the device shown in FIG- URES 1, 2 and 3 is as follows:

The parts, when vacuum is available for the motor 15, normally occupy the positions shown in FIGURE 3. The stop 68 is adjustable, as will be obvious. When such stop is engaged by the button 67, the end of the body of the valve 50 will be spaced from the stop 59. When the button 67 is brought into engagement with the stop 68 the land 55 will move to the lap position relative to the inner end of the port 43. Inherent leakage of air past the land 55 will result in a slight rise in pressure in the chamber 36. This will allow the spring 24 to slightly expand and move the cylinder and valve body 41 slightly to the left of the position shown in FIGURE 3 to disconnect the inner end of the port 43 from the atmospheric groove 54. Thus the valve body 41 and valve 50 will strike a balanced position with respect to each other in which vacuum will be held in the chamber 36, slightly below manifold vacuum, with the spring 34 very slightly expanded from the fully compressed position shown in FIGURE 3. The differential pressures on opposite sides of the piston 23 at such time are sufficient to prevent further expansion of the spring 24. Thus with substantial vacuum present in the chamber 36 while atmospheric pressure is present in the chamber 37, the piston 23 will be near its extreme left-hand limit of movement as in FIGURE 3, and the spring 24 will be held nearly completely compressed.

Under the conditions referred to the treadle 84 will be in position B (FIGURE 1). If the throttle is to be operated, the treadle 34 will be depressed slightly from position B, thus exerting a force against the contact surface 83 of the lever arm 82, and the upper end of this arm will transmit force to the pivot 79, thus shifting the head 35 'and cylinder 22 to the right while the button 67 (FIGURE 3) will remain stationary through its engagement with the stop 68. Under such conditions, the inner end of the port 43 will be cracked to the groove 54 to admit some atmospheric pressure through the line 45 to the motor chamber 36. This reduces differential pressures on opposite sides of the piston 23 and the latter will move to the right. The spring 24 being stronger than the throttle rod return spring 17 (FIGURE 1) a pull will be exerted on the throttle rod 14 to swing the lever 11 clockwise to initiate opening movement of the throttle valve. When the desired engine and vehicle speed has been reached, the treadle 34 may be very slightly backed off to return the valve mechanism to lap position. Differential pressures previously established in the chambers 36 and 37 will then remain unchanged pending further treadle operation, and the piston 23 will remain stationary.

Any desired throttle opening may be provided by operation of the treadle 84. If full throttle opening is desired, the treadle may be moved from position B (FIG- URE 1) to position C. Under such conditions, atmospheric pressure will be established in motor chamber 36 and the spring 24 will expand to its limit to move the piston 23 to its limit of movement with the outer face of the piston 23 engaging the head 35, which will be the piston position shown in FIGURE 2. By manipulation of the treadle 84, any intermediate posit-ion of the piston 23 and any intermediate posit-ion of the throttle valve may be attained. The spring 24, when fully expanded, exerts a force greater than the spring 17 and the latter therefore does not interfere with full throttle opening.

In the event of a failure in power for the motor, vacuum in the chamber 36 will be destroyed. Under such conditions, the rise in pressure in the chamber 36 releases the spring 24 and without moving the throttle rod 14, the lever 11 being held against movement by the spring 17. The spring 24, engaging the motor head 25, will shift the entire motor casing to the left, carrying with it the valve mechanism 49 to move the head 67 substantially out of engagement with the stop 68. Such movement of the motor housing will be transmitted through the pin 79 to the upper end of the lever 80, this lever thus being turned in a counter-clockwise direction. Under such conditions the lever contact point 83 will engage the treadle 84 to move it to position A, which will be the normal treadle position for throttle operation without power.

Assuming that the treadle 84 is in position A, the treadle may be moved from such position to a point nearly in engagement with the toeboard 35 for the full manual operation of the throttle lever 11. When the treadle is moved from position A, the lever will be turned clockwise about its pivot point 81, and the upper end of this lever, through the pin 79, will shift the motor housing to the right from the position shown in FIGURE 1. Such movement of the motor housing will transmit force through the spring 24 to the piston 23, which remains in engagement with the head 35, and the piston rod 23 and throttle rod 14 will move to the right to effect throttle-opening movement of the throttle lever 11, such movement corresponding generally to movement of the pin 79 under the control of the treadle 84.

Generally speaking, the valve mechanism in the form of the invention shown in FIGURE 4 operates in the same manner as the form of the device previously described. Assuming that the source of vacuum fails, the check valve 92 will close and vacuum trapped in the pipes 44 and 93 and vacuum reservoir 94 will continue to provide for the operation of the motor 15 for an appreciable length of time. Assuming that the engine has been stopped with the accelerator treadle in released or idling position, the parts of the device will assume substantially the positions shown in FIGURE 3 with the land 55 substantially in the lap position relative to the inner end of the port 43. Some air leakage will occur around the valve 50, thus leaking some air into the motor chamber 36 to slightly release the spring 24. This spring will then move the cylinder 22 slightly to the left with the button 67 remaining in contact with the stop 68. Under such conditions the seal 90 will move into engagement with the adjacent end of the valve 50 and will thus prevent any further leakage of air into the annular space 52 or any further increase in pressure in the chamber 36. Accordingly sufiicient differential pressure will be present on opposite sides of the piston 23 to maintain it substantially in the power-operative position. This condition will persist for a number of hours, for example over night, and when the motor is started after such period of time, the treadle 84 will be only very slightly above the position B in FIGURE 1, the slight movement of the treadle being due to the very slight movement of the valve body 41 to the left to engage the valve 56 with the sealing ring 9%.

From the foregoing it will be apparent that the present mechanism provides a throttle-operating treadle which normally occupies a relatively low position and from which it must be moved only to a limited extent for full throttle control. In the presently available full power braking systems wherein the brake pedal is movable a distance comparable to movement of the present treadle 84 between positions B and C, the operators right foot not only is more comfortably situated without being bent upwardly, but 'it also may be readily transferred from the brake pedal to the throttle operating treadle of the present device. It also will be apparent that upon a failure in power in the device, the expansion of the spring 24 will move to the left the motor cylinder 22 and valve body 41, carrying with them the pivot point 79 whereby the treadle 84 will be raised to position A from which it has a range of movement between idling and full open throttle positions comparable to movement of a present foot operated throttle treadle.

It is to be understood that the forms of the invent-ion shown and described are to be taken as preferred examples of the same and that various changes in the shape, size, and arrangement of the parts may be made as do not depart from the spirit of the invention or the scope of the appended claims.

I claim:

1. A control mechanism for an engine throttle having a throttle lever, a treadle, a fluid pressure motor comprising a casing unit and a pressure responsive unit, one such unit being connected to said treadle and the other unit being connected to said throttle lever, a valve mechanism operable by said one unit upon operation of treadle to operate said motor to move said throttle lever away from an idling position, said treadle having a first normal position from which it is movable to operate said valve mechanism, and means operable upon a failure of pressure in said motor for establishing a mechanical connection between said treadle and throttle lever through said units and for moving said treadle to a second normal position from which it is movable to manually operate said throttle lever.

2. A control mechanism for the throttle of a motor vehicle engine having a throttle lever and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure operated motor comprising a pair of units constituted respectively by a casing and a pressure responsive unit in said casing, said motor further comprising a valve mechanism, means connecting one of said units to said throttle lever, means connecting said treadle to the other of said units to effect relative movement of said units to operate said valve mechanism, said treadle having .a first normal position relative to the vehicle toeboard from which it is movable a relatively short distance for the full operation of said motor to move said throttle lever a maxim-um distance away from idling position, and means operative upon a failure of pressure in said motor for establishing a mechanical connection between said first two means for the manual operation of said throttle lever and for moving said treadle to a second normal position spaced a greater distance from said toeboard than said first normal position whereby said treadle is movable through a substantial range of movement for the complete manual movement of said throttle lever away from idling position.

3. A control mechanism for the throttle of a motor vehicle engine having a throttle lever and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure operated motor comprising a pair of units constituted respectively by a casing and a pressure responsive unit in said casing, said motor further comprising a valve mechanism made up of a pair of relatively movable units, means connecting one unit of said motor to said throttle lever, means connecting said treadle to the other unit of said motor to effect relative movement of said motor, one unit of said valve mechanism being connected to said other unit of said motor, a stop, the other unit of said valve mechanism normally engaging said stop, means biasing said other unit of said valve mechanism into engagement with said stop whereby movement of said one unit of said valve mechanism by said treadle efr'ects relative movement of said units of said valve mechanism to change the pressure in said motor to effect operation of said throttle lever, said treadle having a first normal position relative to the vehicle toeboard from which it is movable a relatively short distance for the full operation of said motor to move said throttle lever a maximum distance away from idling position, and means operative upon a failure of pressure for said motor for moving said motor bodily away from said stop, to move said treadle lever to a second normal position spaced a greater distance from said toeboard than said first normal position and for establishing a mechanical connection between said treadle and said throttle lever, whereby movement of said treadle from said second normal position manually operates said throttle lever. l

4. A control mechanism for the throttle of a motor vehicle engine having a throttle lever biased to a limit of movement in idling position and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure operated motor comprising a casing connected to said treadle and a pressure responsive unit connected to said throttle lever, a valve mechanism for said motor comprising a pair of relatively movable units one of which is carried by said casing to be moved therewith by said treadle, a stop normally engagging the other unit of said valve mechanism, means biasing said other unit into engagement with said stop whereby movement of said treadle moves said one unit of said valve mechanism to change the pressure in said motor, said treadle having a first normal position relative to said toeboard from which position it is movable a relatively short distance to fully operate said motor to move said throttle lever its maximum distance from an idling position, and resilient means operative upon a failure of pressure in said motor t'or moving said casing relative to said pressure responsive unit to move said other unit away from said stop and to move said treadle to a second normal position substantially higher than said first normal position, said resilient means establishing a mechanical connection between said casing and said pressure responsive unit whereby said treadle is movable from said second normal position for the full manual operation of said throttle lever.

chamber fails, said spring will exert reactionary forces against said pressure responsive unit and said casing to bodily move the latter.

6. A control mechanism for the throttle of a motor vehicle engine having a throttle lever biased to a limit of movement in idling position and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure motor comprising a casing connected to said treadle and a piston therein connected to said throttle lever and dividing said casing to form an atmospheric pressure chamber in the end of said casing remote from said throttle lever and a vacuum chamber in the other end of said casing, a valve mechanism having a vacuum line and normally maintaining vacuum in said vacuum chamber, a spring in said vacuum chamber reacting against said pressure responsive unit and the adjacent end of said casing, said treadle having a first normal position relative to said toeboard and having connection with said valve mechanism whereby movement of said treadle operates said valve mechanism to progressively supply air to said vacuum chamber to progressively release said spring to move said pressure responsive unit and operate said throttle lever, and a stationary stop normally engaging an element of said valve mechanism, failure of vacuum in said vacuum chamber releasing said spring to effect bodily movement of said motor casing away from said stop to raise said treadle to a second normal position higher relative to said toeboard, said spring establishing mechanical connection between said pressure responsive unit and said casing for the manual operation of said throttle lever upon movement of said treadle from said second normal position.

7. A mechanism according to claim 6 wherein said valve mechanism includes a housing connected to said casing to move therewith and in which said one element is movable.

8. A control mechanism for the throttle of a motor vehicle engine having a throttle lever and a throttle rod, and wherein the motor vehicle is provided with a toeboard, a first spring biasing said throttle lever to a limit of movement in idling position, a treadle mounted above said toeboard, a fluid pressure motor comprising a casing connected to said treadle and a piston therein connected to said throttle rod and dividing said casing to form a pair of chambers, a valve mechanism normally connecting a pressure source to one of said chambers to maintain diiferential pressures on opposite sides of said piston to maintain the latter adjacent one end of said cylinder in a normal position in which said throttle lever is in idling position, a second spring reacting against said pressure responsive unit and said casing to tend to overcome differential pressures in said chambers, said treadle having a first normal position relative to said toeboard and having connection with said valve mech anism whereby the latter is operable by said treadle to progressively reduce said differential pressures to progressively release said spring to move said pressure responsive unit and operate said throttle rod, said valve mechanism comprising a pair of elements one of which is fixed with respect to said casing, a stop normally engaging the other element of said valve mechanism, and means biasing said other element into engagement with said stop whereby movement of said one element of said valve mechanism by said treadle reduces said differential pressure, failure of said differential pressure releasing said spring to effect bodily movement of said motor casing away from said stop to raise said treadle to a second normal position higher than said first normal position, and for establishing mechanical connection between said treadle and said throttle rod for the manual operation of said throttle rod upon movement of said treadle from said second normal position.

9. A mechanism according to claim 8 wherein said source is a source of vacuum, the motor chamber toward said throttle rod being a vacuum chamber normally connected to said source, said spring being a compression spring arranged in said vacuum chamber.

10. A mechanism according to claim 8 wherein said source is a source of vacuum, the motor chamber toward said throttle rod being a vacuum chamber normally connected to said source, said spring being a compression spring arranged in said vacuum chamber, said second spring, when expanded, being stronger than said first spring and serving to establish said mechanical connection between said treadle and said throttle rod.

11. A control mechanism for the throttle of a motor vehicle engine having a throttle lever biased to a limit of movement in idling position and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure motor comprising a casing connected to said treadle and a pressure responsive unit therein connected to said throttle lever and dividing said casing to form a pair of chambers, a valve mechanism comprising a housing fixed to said motor casing and a slide valve therein projecting from the end of said motor opposite said throttle lever, said valve mechanism being connected to a pressure source and normally maintaining differential pressures in said motor chambers to maintain said pressure responsive unit in the end of said motor casing toward said throttle lever, a spring engaging said casing and said pressure responsive unit to tend to move the latter toward the other end of said motor casing, said treadle having a first normal position relative to said toeboard, a stationary stop at the end of said motor opposite said throttle lever and normally engaging said slide valve, means biasing said slide valve into engagement with said stop, motion transmitting means connecting said pedal to said casing to move the latter toward said stop while the latter remains in engagement with said slide valve, to operate said valve mechanism to relieve said dilferential pressure for movement of said piston by said spring to operate said throttle lever, failure of said differential pressure releasing said spring to react against said casing to move it toward said throttle lever and to move said slide valve substantially away from said stop, and to move said treadle to a higher normal position relative to said toeboard, said spring serving to establish mechanical connection between said casing and said throttle lever for the manual operation of said throttle lever when said treadle is moved from said higher normal position.

12. A mechanism according to claim 11 wherein said motion transmitting means comprises a control lever pivotally supported between its ends, said control lever engaging at one end beneath said treadle and being connected at its other end to said casing whereby the latter is moved toward said stop to operate said valve mechanism upon depression of said treadle from said first normal position, for progressively reducing differential pressures in said chambers.

13. A mechanism according to claim 11 wherein the motor chamber toward said throttle lever is a vacuum chamber, said source being a source of vacuum, said spring being a compression spring arranged in said chamber and engaging at opposite ends against the adjacent end of said casing and against said pressure responsive unit.

14. A mechanism according to claim 11 wherein the motor chamber toward said throttle lever is a vacuum chamber, said source being a source of vacuum, said spring being a compression spring arranged in said chamber and engaging at opposite ends against the adjacent end of said casing and against said pressure responsive unit, said motion transmitting connection comprising a control lever pivoted intermediate its ends, said control lever engaging at one end beneath said treadle and being connected at its other end to said casing whereby movement of said treadle from said first normal position moves said casing toward said stop to progressively admit air to said vacuum chamber to progressively release said spring to move said piston and thus move said throttle lever away from idling position.

15. A mechanism according to claim 11 wherein said valve housing is provided with a seal engageable by said slide valve when the latter is in normal position to prevent leakage of pressure past said slide valve, said source being a fluid line having a check valve therein to trap pressure therein, and an auxiliary pressure reservoir connected to said line between said check valve and said valve mechanism.

16. A control mechanism for an engine throttle having a throttle lever, a treadle, a fluid pressure motor comprising a casing unit and a pressure responsive unit, one such unit being connected to said treadle and the other unit being connected to said throttle lever, a valve mechanism operable by said one unit upon operation of said treadle to operate said motor to move said throttle lever away from said idling position, and means operable upon a failure of pressure in said motor for establishing a mechanical connection between said units for the manual operation of said throttle lever by said treadle.

17. A control mechanism for the throttle of a motor vehicle engine having a throttle lever and wherein the motor vehicle is provided with a toeboard, a treadle mounted above said toeboard, a fluid pressure operated 1 motor comprising a casing unit and a pressure responsive unit therein, a valve mechanism for said motor operable by one of said units, means connecting the other of said units to said throttle lever, means connecting said treadle to said one unit to operate said valve mechanism, and means operative upon a failure of pressure in said motor for establishing mechanical connection between said units whereby treadle operation of said one unit will effect movement of said other unit to operate said throttle lever.

- References Cited by the Examiner UNITED STATES PATENTS 2,848,980 8/58 Ayers 91469 X 2,910,147 10/59 Fishtahler 188-452 3,063,427 11/62 Hill 91--391 3,103,854 9/63 Price et a1 91-391 X 3,104,590 9/63 Kellogg et al. 123--103 X FRED E. ENGELTHALER, Primary Examiner.

SAMUEL LEVINE, Examiner. 

1. A CONTROL MECHANISM FOR AN ENGINE THROTTLE HAVING A THROTTLE LEVER, A TREADLE, A FLUID PRESSURE MOTOR COMPRISING A CASING UNIT AND A PRESSURE RESPONSIVE UNIT, ONE SUCH UNIT BEING CONNECTED TO SAID TREADLE AND THE OTHER SUCH UNIT BEING CONNECTED TO SAID TREADLE AND THE OTHER UNIT BEING CONNECTED TO SAID THROTTLE LEVER, A VALVE MECHANNISM OPERABLE SAID MOTOR TO MOVE SAID THROTTLE LEVER AWAY TO OPERATE SAID MOTOR TO MOVE SAID THROTTLE LEVER AWAY FROM AN IDLING POSITION, SAID TREADLE HAVING A FIRST NORMAL POSITION FROM WHICH IT IS MOVABLE TO OPERATE SAID VALVE MECHANISM, AND MEANS OPERABLE UPON A FAILURE OF PRESSURE IN SAID MOTOR FOR ESTABLISHING A MECHANICAL CONNECTION BETWEEN SAID TREADLE AND THROTTLE LEVER THROUGH SAID UNITS AND FOR MOVING SAID TREADLE TO A SECOND NORMAL POSITION FROM WHICH IT IS MOVABLE TO MANUALLY OPERATE SAID THROTTLE LEVER. 